WASHINGTON
— The high hopes of just a few weeks ago that the United States would aggressively reengage in resolving the Israeli-Palestinian conflict are beginniing to dim.

The "window of opportunity" that opened after the death of Palestinian leader Yasser Arafat and Israel's withdrawal from Gaza has not closed yet, experts say. But concern is growing in some quarters that the engine that has driven forward movement in the past - close US involvement - is not revving up.

The reasons for US hesitancy are varied. For one, the political climates are churning both in Israel and the Palestinian territories. For another, and just as important, the White House and much of Congress see this delicate period as above all a testing time for Palestinian leadership.

"This is not going to be the time of a major 'road map' breakthrough," says David Makovsky, director of the Project on the Mideast Peace Process at the Washington Institute for Near East Policy, referring to the internationally accepted plan for achieving Palestinian statehood.

The Palestinians are entering a pre- election season, with legislative elections set for January. Israeli Prime Minister Ariel Sharon, who this week narrowly won a confidence vote in his Likud party, is not expected to be in the mood for the kinds of concessions the Palestinians would like to see soon regarding West Bank settlements and relaxed security controls.

"Both parties are entering political seasons," Mr. Makovsky adds, "so it's not a time for diplomatic breakthroughs."

At the same time, the Bush administration and many in Congress see the onus falling on Palestinian President Mahmoud Abbas to stop all militant activities from inside the territories against Israel. In congressional testimony last week, Assistant Secretary of State for Near East Affairs David Welch said Palestinian performance in "dismantl[ing] the infrastructure of terror" has been "far from satisfactory."

The militant group Hamas this week offered a ceasefire, but only after days of mortar fire into Israel from Gaza caused Israel to attack in retaliation. In Congress, those in both parties already reflect a sense of foreboding at prospects of Hamas participation in a Palestinian government.

With President Bush focused on domestic concerns, experts do not expect to see any major peace-process initiatives coming from the White House. "Bush has been knocked over by these hurricanes. He's totally distracted," says Michael Hudson, a Mideast expert at Georgetown University in Washington. "I don't expect to see anything new from the US, and that's too bad because it's a critical moment in Gaza."

That is not to say the US is doing nothing. Mr. Bush named Lt. Gen. William Ward as US coordinator for security assistance to the Palestinians, and the "Quartet" of players overseeing road-map implementation - the US, Russia, the European Union, and the United Nations - made former World Bank president James Wolfenson its envoy on economic issues.

The US also earmarked $225 million this year to fire up the Palestinian economy - to create jobs in the hope of fostering support for Mr. Abbas, also known as Abu Mazen, before the crucial January elections. That is part of the $700 million expected to begin flowing soon as part of Palestinian economic revitalization efforts, Mr. Wolfenson has said.

Wolfenson is the "de facto American envoy - he talks to [Secretary of State Condoleezza] Rice all the time," says the Washington Institute's Makovsky.

All of that, though, amounts to less White House political capital than many had wanted. This period, say experts and officials linked to the conflict, is the best chance for progress since the intifada began in 2000. Time is short for progress on "access for security" issues - better Palestinian access to jobs in exchange for confidence-building security controls - that will be key to Abbas's political future.

"I don't think it's too late," Dennis Ross, a lead diplomat on the peace process during both the first Bush and the Clinton presidencies, said recently in Washington. But the US is "waiting for the period to play itself out," he said. "I'm afraid if you wait you will have missed the boat."

That "boat" may include something broader than the way to Palestinian statehood, some say. Noting that Karen Hughes, new State Department public diplomacy chief and former White House adviser, is currently on a "listening tour" of the Middle East, Georgetown's Mr. Hudson says the White House could do a lot more to burnish America's image in the region by making the peace process a top priority.

"A vigorous effort to improve the Palestinians' conditions and move the process forward is what would really help us out in the region," Hudson says. "There doesn't seem to be an understanding of that."